Improvement in sickle-grinders



2 Sheets-She et 1. H. S. S T E V E N S. SICKLE-GRINDER. No.183,987.Patented 0ct.31,1876.

WITNESSES INVENTOR %0mw e6 d 04/z/ ATTORNEYS 2 Sheets-SheetZ. H. S.STEVENS.

SICKLE-GRINDER.

No. 183,987. Patented 001;. 31. 1876.

G 1/ T a o 0 2 WITNESSES NVEN OR Q cCtS/S m 65: WW,

g IZ6%W. C ATTORNEYS,

UNITED STATES PATENT OFFICE.

HOMER S. STEVENS, WAUKEGAN, ILLINOIS, ASSIGNOR OF ONE-HALF HIS RIGHT TOJOHN F. POWELL, OF SAME PLACE.

IMPROVEMENT IN SICKLE-GRINDERS.

Specification forming part of Letters Patent No. 183,987, dated October31, 1876; application filed To all whom it may concern Be it known thatI, HoMEE S. STEVENS, of Waukegan, in the county of Lake and State ofIllinois, have invented a new and valuable Improvement inSickle-Grinders; and I do hereby declare that the following is a full,clear, and exact description of the construction and operation of thesame, reference being had to the annexed drawings, making a part of thisspecification, and to the letters and figures of reference markedthereon.

Figure 1 of the drawings is a representation of a side elevation of mysickle-grinder, and Fig. 2 is a front elevation of the same. Fig. 3 is adetail view thereof. Fig. 4 is a vertical section through the line a; m,Fig. 2.

This invention relates to devices for operatin g grindstones used insharpening the knives or cutting-blades of harvester-sickles; and itconsists in the employment of special devices, whereby an oscillatoryand rotary motion is at the same time imparted to a grindstone, as willbe hereinafter more particularly described and claimed.

In the annexed drawings, A A designate two inclined andupwardly-converging standards or supporting-beams, forming one side ofthe frame of my device. A designates two similar standards on theopposite side of the same frame. Each pair of said standards is rigidlysecured together at their upwardlyconverging ends. On the top of each ofsaid side supports A and A 'is secured one of two upright andvertically-slotted metal plates, B B. Said plates support a cross-piece,O, which is secured to the said plates B B by clampscrews 0 c, by whichsaid cross-piece is adjusted vertically, as said clamp-screws areallowed to slide up and down in slots b b of said plates B B, saidscrews being tightened at any point desired. To the under side of saidcross-piece O is rigidly secured a metal plate or casting, D, which hason its rear end upright perforated lugs d, between which lugs is pivotedthe rear end of a sickle'holder, E. Said sickle-holder may be thrownupward and backward out of operation or turned forward and downward, soas to hold the blades of the sickle immediately above a grindstonehereinafter described. Said holder is constructed with sickle-supportingarms E E ex- September 2, 1876.

tending backward from the forward end of said holder on either sidethereof. It is also provided with lugs e e and a projecting lip, 0.Between said lugs e e is pivoted, by the middle of its length, aclamping-bar, F, which is provided in front with a handle, F and at itrear end with a presser-foot, F Said clamping-bar is screw-tapped infront of its pivotal point to receive a vertical adjusting thumbscrew,G, which bears against the surface of lip or flange 0. By screwing saidthumbscrew up through said clamp-bar F the said presser-foot F israised, so as to allow the harvester-sickle to be introduced below itand upon supporting-arms E E, said arms being a little below the planeof said holder E. By screwing said thumb-screw down through saidscrew-tapped clam p-bar F, said presser-foot F is forced tightly downupon the said sickleblade, clamping it against the said supportingarms EE. The handle F is convenient for throwing the presser-barorclamp-barand holder back out of operation, as already stated. H is a metalwater-trough rigidly secured to supporting-frame A A by means ofbrackets or short L-shaped arms I. J designates a grimlstone, turning soas to keep its lower side in said trough, and journaled by short axle Kin the upper ends of U-shaped metal tilting frame L. Said frame ispivoted somewhat below its center of gravity to fixed trough H. One ofthe sides of said frame is provided with an arm, M, which is rigidtherewith, and is curved outwardly, up wardly, and forwardly, as shown.Said outward or lateral curve of arm M is for the purpose of allowingthe free rotation of cog-wheel N, which is fast on one end of axle K,and which rotates grindstone J. The forward and upward curve of saidrigid arm M is for the purpose of providing a bearing for horizontallaterally-extending rotating shaft P, which turns in a perforation ofsaid arm. An additional bearing for said rotating shaft is furnished bythe perforated end of an additional arm or bar, Q, rigidly connected tothe upper end of tilting frame L near (though above) the point ofattachment of said arm M, and extending horizontally forward. Saidrotating shaft is operated by a crank, B, and carries a cog-wheel, S,which meshes with cog-wheel N, and communicates motion thereto. By meansof the above-described devices, when the said crank is turned the saidgrindstone is made to rotate, dipping into the water in tank H below,and grinding the sickle held by holder E and clamp-bar F above.

The periphery of said grindstone J is constructed with a central ridge,j, from which slope bevcls J J toward its sides. This shape enables itto sharpen two of the pointed sickle-blades or cutting-knives at thesame time, since the ridge j sharpens the meeting parts of said pointedblades at the deepest part of the notch intervening between any two ofsaid blades, and the diverging bevcls J J conform to and sharpen thecontiguous diverging edges of said blades or cuttingknives.

As said sickle and its blades are held in a horizontal or nearlyhorizontal position, it becomes desirable to give to said grindstone anoscillatory as well as a rotary motion; otherwise, said blades would beground at the point where they would touch the highest part of theperiphery of said grindstone; but nowhere else. To obviate thisdifficulty and produce said oscillating motion of said grindstone, Iemploy the following devices: T designates an in wardly-extendin gbracket, rigidly secured to inclined standards A of thesupporting-frame, and U designates a bar pivoted thereto by its rearend, extending horizontally forward, and ending in an oblong'longitudinal loop, U, which surrounds grindstone-axle K. V designates aprojecting-plate or pro longation of the bar U provided with a lateralpivot-pin, on which is pivoted a triangular or other eccentric plate, W.To said plate W is eccentrically secured the end of rotating shaft P.The construction of said plate W causes the rotation of shaft P tobecome eccentric, and thereby, through its supporting-arms, communicatesan oscillating motion to the said tilting frame, which supports the saidgrindstone. This causes the said grindstone to oscillate as it rotatesupon its axis. The result of this compound oscillating and rotatingmotion is that the said grindstone is brought in contact with every partof the edges of each of said sickleblades, and sharpens them properly.

If cog-wheels N and S were of the same diameter, the periphery of saidgrindstone would be unevenly worn, since the same part of said peripherywould come into contact (during the rearward and upward part of theoscillation) with the knives at each rotation of said wheel, while theremainder of said periphery would undergo less friction or none at all.Thus, there would be a point of greatest wear and an opposite point ofno wear, or very slight wear; and the intervening parts of the wheelwould be worn in regular gradation from the former point toward thelatter. To obviate this 1 make cog-wheel S somewhat larger thancog-wheel N, so that when the shaft P is rotated once, the wheel N andgrindstone J will be turned once and somewhat more.

Thus the said grindstone is made to present a new part of its peripheryto receivethe greatest wear at each oscillation. As these changes recurin a regular cycle the periphery of said grindstone will be worn almostperfectly even. The same result will be attained by making cog-wheel Nlarger than cog-wheel S; but as the grindstone will then revolve lessrapidly, the grinding will be rather less efiective in proportion to thenumber of turns of said crank.

Bar U prevents the said grindstone J, axle K, and the devices attachedthereto from falling backward and forward. The pivotal attachment ofsaid bar allows it to yield vertically, and thereby preventsaxle K frombinding in loop U. This yielding motion causes the pivot-pin V ofeccentric plate W to move up and down in an arc while the sl: aft P isbeing rotated, so that said shaft does not rotate or revolve about saidpivot-pin, but about a point not far from the middle of the are sodescribed. Water-trough H is made long enough to allow the backward andforward movement of grindstone J in the course of its oscillation abovedescribed. Gross piece 0 prevents sickleholder E from falling too farforward and downward. Said sickle-holder is capable of yielding, in anupward direction, to prevent injury to the sickle from the saidoscillating movement of the said grindstone J.

Various modifications may be introduced without departing from thespirit of my invention-for instance, shaft 1? may be turned by any formof gearing instead of a crank; pulleys and a connecting-band may besubstituted for cog-wheels N and S; eccentric W may be oblong instead oftriangular, or may have any other suitable shape; screw-threaded rodsand clamping-nuts may be used for adjusting cross-piece G and thematerials used may be varied in any way which does not impair theefficiency of the devices.

What I claim as new, and desire to secure by Letters Patent, is-

1. The U shaped tilting frame L, surrounding and pivoted to thewater-trough near its lower end, and having bearings at its upper endfor the grindstone-axle, in combination with the pivoted arm U, havingloop U ,whereby the grindstone is allowed to rotate and oscillate in thewater-trough, substantially as described.

2. The tilting frame L, carrying the grindstone-axle K, in combinationwith the pivoted arm U, having loop U, and eccentric plate W, operatedby suitable mechanism, substantially as described, and for the purposeset forth.

In testimony that I claim the above I have hereunto subscribed my namein the presence of two witnesses.

HOMER S. STEVENS.

Witnesses:

JOHN F. PowELL, D. M. ERSKINE, Jr.

